The present invention concerns a hinge device for a front hood of a motor vehicle, which can be adjusted from a normal position to a protective position in the event of a collision. The present invention likewise concerns a motor vehicle provided with such a hinge device, as well as a method for adjusting such a hinge device.
With the hinge device of this kind, a pedestrian impact protection function should be realized, whereby in the event of a collision of the respective motor vehicle with a pedestrian or a bicycle rider the front hood is moved by a defined distance away from the vehicle body. In this way, at the same time, the distance of the front hood from a component located underneath, usually a rigid component such as a drive assembly, is increased, which may lessen the risk of injury to the pedestrian or bicycle rider struck by the vehicle.
The systems serving for impact protection have generally been known for a rather long time. In these systems, the front hood of a motor vehicle is actively lifted by means of an actuator upon sensor-controlled detecting of a possible front collision with a pedestrian.
Thus, from DE 101 52 621 A1 there is known an arrangement of a front hood on a motor vehicle with at least one rear hinge device—looking in the main direction of travel—and at least one front lock for retaining or lifting the front hood from a normal position to a protective position. A lifting of the front hood in its rear area occurs by activation of an actuator. A lifting of the front hood in its front area then occurs by a forced coupling device, especially a link guide, which forcefully carries along the front area of the front hood when lifted in its rear area. Furthermore, another actuator may optionally be provided at the front area of the front hood, supporting the force-guided movement of the front hood in the event of a collision.
A more accurate presentation of a hinge device known from the prior art is disclosed in DE 10 2009 040 413 A1. This document discloses a front hood of a motor vehicle, which can be adjusted from a normal position to a protective position in the event of a collision, with a body fastening part, which can be attached to the body of the motor vehicle, a front hood fastening part to which the front hood may be attached, a front hood hinged lever, to which the front hood fastening part is hinged, a first hinged lever and a second hinged lever, each of them hinged on the one hand to the body fastening part and on the other hand directly or indirectly to the front hood hinged lever, as well as an actuator equipped with a tappet, which can be brought into contact by an actuator surface against a front hood hinged lever contact surface.
It should be noted that the term “actuator” in this patent application is used as a generic term for a corresponding drive in its entirety, known from the prior art, especially DE 10 2011 106 513 A1 and FR 2883606 A1, but also synonymously in an individual case for its components, especially an actuator tappet or piston.
The hinge device known from DE 10 2009 040 413 A1 has a reliable design. However, it has a relatively large actuator, whose actuator surface in theory cannot always lie fully against the front hood hinged lever contact surface. This might present the risk of a skewing or twisting of the actuator or its tappet, which could lead to an inadequate raising movement and thus an undesirable positioning height of the front hood.
The problem which the present invention proposes to solve is to rule out the above-mentioned theoretical risk.
According to the invention, it is therefore provided that a front hood surface and a lifting device with an actuator contact surface and a front hood contact surface are provided on the front hood fastening part, wherein the actuator surface can be brought to bear against the actuator contact surface and the front hood contact surface can be brought to bear against the front hood surface during an adjustment from the normal position to the protective position. The distance which is provided substantially in the actuating direction of the actuator on the lifting device, between the front hood contact surface and the actuator contact surface, is greater than the distance between the actuator surface and the front hood hinged lever contact surface.
With the hinge device according to the invention it is advantageously made possible to employ a shorter actuator or actuator tappet than in the current prior art, since this directly raises the front hood fastening part—and thus the front hood—at a very early stage. In fact, the actuator drives the front hood fastening part via the lifting device provided according to the invention even before its actuator surface comes to bear against the front hood hinged lever contact surface. Thus, not only is the risk of a skewing or twisting of the actuator or the tappet minimized on account of the shorter length as compared to the prior art, but also the initially only direct application of force from actuator surface to actuator contact surface as well as front hood contact surface and front hood surface results in improved kinematics of the front hood fastening part and thus the front hood of the motor vehicle. Since a shorter actuator than in the prior art can be chosen for the hinge device according to the invention, the benefit of less installation space required for the hinge device is also obtained, since the lifting device which lengthens the path of the actuator is smaller in size than a conventional actuator.
Advantageously, it can be provided that the lifting device is mounted so as to be able to pivot about an axis arranged on the front hood hinged lever. In this way, already known standard components in automotive engineering can be used, especially axles which can be designed as pivot pins.
Advantageously, it can be provided to design the actuator contact surface of the lifting device and/or the front hood hinged lever contact surface complementary to the actuator surface in order to further improve the reliability of the respective pairings. In this case, a substantially normal or approximately perpendicular application of the force produced by the actuator or its tappet against the lifting device and the front hood hinged lever is specifically achieved during the entire raising process. Alternatively or additionally, it may likewise be provided advantageously to design the front hood contact surface complementary to the front hood surface; the aforementioned benefits will apply appropriately.
The front hood surface may advantageously be designed as a flange protruding from the front hood fastening part. The arrangement of a flange on a hinge part, especially a front hood fastening part, is easily possible with conventional means of fabrication in mechanical engineering. Furthermore, it may be provided advantageously that the front hood surface designed as a flange has an opening, through which a fastener, especially a screw, can be led, by which the front hood can be fastened and secured on the flange-shaped front hood surface and thus on the front hood fastening part.
In order to prevent an unintentional raising of the front hood of the motor vehicle, according to the invention a securing pawl is provided on the lifting device, which is optionally coupled to a pin attached to the front hood hinged lever. The pin provided according to the invention is only released by the securing pawl when the actuator swivels and/or lifts the lifting device by a defined amount. However this securement not only prevents the aforementioned undesired raising movement during the driving of a motor vehicle according to the invention, but also makes possible a normal opening of the front hood in normal position, for example in order to undertake servicing work on subassemblies situated underneath the front hood.
An especially advantageously compact design of the hinge device according to the invention is achieved when the front hood hinged lever contact surface is designed as a flange, which protrudes from the front hood hinged lever and has a recess in which the lifting device can move. With this design, the lifting device can move virtually sideways past the front hood hinged lever and through the front hood hinged lever contact surface when the front hood is adjusted from a normal position to a protective position.
In another embodiment of the invention it may be provided that the distance existing substantially in the actuating direction of the actuator between the actuator surface and the front hood hinged lever contact surface and the distance existing between the actuator surface and the actuator contact surface is equal to zero. Thus, in this case, the actuator surface drives both the front hood hinged lever contact surface—and thus the front hood hinged lever—at the same time as the front hood fastening part. Due to the fact that now the front hood hinged lever is also driven, the actuator contact surface detaches from the actuator surface and thus the lifting device itself detaches from the actuator surface, so that the further raising movement of the hinge device according to the invention can occur in a safe and dependable manner.
The above-mentioned problem is likewise solved with a motor vehicle having a hinge device of the above-mentioned kind. The benefits mentioned above in regard to the hinge device itself likewise apply to a motor vehicle equipped with it.
Finally, the above-mentioned problem is solved by a method according to the invention, which calls for the following steps:
1. Starting an extension of the actuator provided with an actuator surface from the normal position;
2. Bringing the actuator surface into contact with the actuator contact surface located on the lifting device under continuing extension of the actuator;
3. Bringing the front hood contact surface located on the lifting device into contact with the front hood surface under continuing extension of the actuator;
4. Bringing the actuator surface into contact with the front hood hinged lever contact surface under continuing extension of the actuator;
5. Bringing the actuator contact surface out of contact with the actuator surface under continuing extension of the actuator;
6. Ending of the extension of the actuator once a desired position of the actuator surface has been reached.
With these method steps according to the invention it is advantageously possible to lift the front hood by a driving of the front hood fastening part already before the actuator even touches the front hood hinged lever at all. The benefits described in connection with the hinge device according to the invention thus also apply to the method according to the invention.
This holds, in particular, when the securing pawl under continuing extension of the actuator is released from the pin attached to the front hood hinged lever after bringing the front hood contact surface into contact with the front hood surface.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.